Composite die member



Aug. 4, 1970' R. B. CUBITT COMPOSITE DIE MEMBER 2 Sheets-Sheet 1Original Filed March 26, 1963 INVENT Robert Bruce 0 g- 4, 1970 R. B.CUBITT 3,522,633

COMPOSITE DIE MEMBER Original Filed March 26, 1963 2 Sheets-Sheet 2 42 245 Z: 6 E: w 1 7 1 Y i a: v 27 (L h h T9 I G26 INVENTOR. Ruben Bruce60bit! JW 73216;, v 74 11/17 Niamey! United States Patent 3,522,633COMPOSITE DIE MEMBER Robert Bruce Cubitt, Jersey City, N..I., assignorto Colgate-Palmolive Company, New York, N.Y., a corporation of DelawareOriginal application Mar. 26, 1963, Ser. No. 268,031, now Patent No.3,408,436. Divided and this application Jan. 15, 1968, Ser. No. 711,820

Int. Cl. B29c ]/02 US. Cl. 18-47 4 Claims ABSTRACT OF THE DISCLOSUREThis is a division of my copending application Ser. No. 268,031 filedMar. 26, 1963, now Pat. No. 3,408,436 for Method for Making CompositeDie.

This invention relates to dies for the pressing of soap or likerelatively soft material into bars, cakes or any desired compact form,and particularly to dies of this type having a specially formed designbearing section, and to methods and apparatus for making the same.

In its preferred embodiment the invention is concerned with dies forpressing large numbers of small bars of soap of standard size such asthe individual cakes supplied in each room by hotels, motels and thelike. These establishments have recently required that a name or someother distinct legend or shape be formed on the soap bar to identify thesame and as a form of advertising.

Most larger soap pressing dies are formed with internal stainless steelor hard plastic forming surfaces that are smooth and polished except forany intaglio or relief design that may be cut thereinto, which meansthat a separate die is needed for each soap surface design. This iscommercially practical where hundreds of thousands of large soap barsare pressed from the same die day in and day out, but it is noteconomical or practical to provide a separate permanently inscribed soapdie for each hotel or like customer who may order only a few thousandbars of soap but once or at irregular intervals.

It has been proposed for taking care of this trade to provide one ormore soap contacting surfaces of the die members with removable andreplaceable panels bearing the respective designs, but difficulties havebeen encountered in making these fit with enough accuracy to avoidundesired marking of the soap bar, and besides the processes of makingand changing the die panels are slow and expensive in terms of labor.

The present invention provides a solution for this problem by makingcomposite soap die members containing accurately molded panel inserts ina speedy inexpensive manner.

It is therefore the major object of this invention to provide a novelsoap pressing die structure having one or more accurately formed diesurface insert sections, and the novel method of speedily andinexpensively making such die structure.

Another object of the invention is to provide a novel soap pressing diestructure wherein part of the internal soap contacting and formingsurface of the die is a specially formed plastic panel for providing adesired design on the pressed soap .bar.

A further object of this invention is to provide a novel method ofmaking a soap die member having a soap contacting and forming surfacewherein an insert panel or the like is formed as by molding or castinginto a recess in said surface, said panel having an exposed surfacewhich except for a design is essentially a continuation of said diepressing surface, and wherein the incorporated panel is removable formolding or casting a substitute panel.

A further object of the invention is to provide a rigid soap pressingdie having a smooth soap contacting surface such as metal formed with arecess, and a design forming insert panel of moldable plastic in saidrecess.

Another object of the invention is to provide a novel apparatus formaking a soap die having a molded plastic panel in a recess in its soapcontacting and forming surface wherein the die member is clamped over amaster design bearing blank that closes the recess during moldmg.

Further objects of the invention Will appear as the description proceedsin connection with the appended claims and the annexed drawings wherein:

FIG. 1 is a top plan view of a metal soap pressing die upper memberaccording to a preferred form of the invention;

FIG. 2 is a section on line 2-2 of FIG. 1, showing the soap pressingsurface recess for receiving the panel;

FIG. 3 is a section on line 33 of FIG. 2;

FIG. 4 is a bottom plan view of the soap die member of FIG. 1 showingthe panel recess;

FIG. 5 is a section similar to FIG. 2, but showing the insert panel inthe recess;

FIG. 6 is a bottom plan view of the die member of FIG. 5 showing thepanel surface design;

FIG. 7 is a generally exploded view partly in section showing the partsin position for carrying out the method of the invention;

FIG. 8 shows the parts of FIG. 7 in operative assembly and after theplastic material has been introduced to form the insert; and

FIG. 9 is a top plan view of the jig base showing the master panelrecess.

Referring to FIGS. 1-6, the soap die assemblies comprise a die box 10and associated upper and lower die members 11 and 12, which arerelatively separable vertically for the introduction of a body of soapinto the cavity 13 therebetwcen to be pressed and compacted into theshape and size of the cavity.

Preferably the die box and die member arrangements are the same asdisclosed in United States Letters Patent to Sweet et al. No. 2,965,946issued Dec. 27, 1960, to which reference is made for further detail.

Lower die member 12 has recessed therein a smooth soap contactingsurface 14, and upper die member 11 has recessed therein a smoothrecessed soap contacting surface 15.

In the illustrated embodiment, die members 11 and 12 may be hard wearresistant steel blocks usually of stainless steel, and the recessedforming surfaces 14 and 15 are smooth without abrupt corners. The sizeand shape of cavity 13 are the size and shape of the desired soap bar.The upper die member 11 has a continuous sharp edge 16 arounds its lowercircumference surrounding recess 15, and lower die member 12 has asimilar continuous sharp edge 17 around its upper circumferencesurrounding recess 14.

Any conventional arrangements may be used for relative movement of thedie members 11 and 12 and introduction of the body of soap therein, suchas the arrangements disclosed in said Sweet et a1. patent.

As shown in FIGS. 24 the metal die member 11 has surface 15 recessed toform a panel mounting recess 18. This recess is generally rectangularwith rounded circumferential corners and having a flat bottom face 19parallel to the medial portion of die surface 15. The sides 21 and 22 ofrecess 18 are preferably flat and intersect face 19 at right angles.

Completely filling recess 18 is a panel 23 of relatively hard plasticmaterial (FIGS. and 6) which has an exposed smooth flat surface 24 atthe same level as, and substantially a continuation of, die surface 15.

Integrally formed on panel surface 24 is a design 25 shown here inrelief to project within cavity 13, and adapted to impress an intagliodesign into the compacted soap bar. Alternatively of course the design25 could be intaglio, or even a combination of intaglio and relief, withcorresponding formation of the compacted soap bar surface.

The panel 23 is secured tightly in place, either by its mode of assemblyas will appear, or by separate locking elements as also will appear, ora combination of both.

Should a different design than that at 25 be desired for the soap bar,it is necessary only to displace panel 23 out of recess 18 and replaceit with another panel that is identical, except for surface design, andsecured sufficiently tightly in place to stay there during die formingof the soap bar.

A preferred method of forming a panel 23 in place on the metal diemember will now be described.

The metal die member 11 is formed with three bores 26 leading from thetop to open into recess 18, as shown in FIG. 2.

Referring now to FIGS 7-9, the die member of FIG. 2 is placed in a jigcomprising a rigid supporting base 27 formed with a central opening 28surrounded by an annular recessed shoulder 29. Stepped at a higher levelthan the horizontal planar bottom of shoulder 29 is a further annularflat horizontal shoulder 31 having a planar bottom parallel to that ofshoulder 29'.

Seated on shoulder 29 is a master blank 32 of hard non-deformableplastic which circumferentially fills the shouldered recess at 29 andprojects above it. The fiat upper horizontal surface 33 of blank 32 isformed at 34 in reverse intaglio with the design eventually desired tobe formed on the panel insert 23.

Die member 11, which circumferentially fills shouldered recess 31, ismounted over the blank 32 with the die surface 15 engaging the upperside of blank 32 and the die is held tightly thereby posts 35 upstandingfrom holes 36 in the base 27, clamps 37 extending over its upper end,and nuts 38 tightening down on the clamps on the threaded upper ends ofposts 35. Thus blank 32 is clamped between the die 11 and base 27.

The entire upper surface of blank 32 is coated with i a partingcompound, to prevent it sticking to die surface 15 or the molded insertpanel to be described.

With the parts so clamped as in FIG. 8, it will be noted that the rim ofthe upper fiat surface 33 of the blank 32 smoothly and tightly contactsthe upper die member surface 15 all around the cavity 18.

Now a suitable moldable material is poured or injected through thecentral bore 26 until cavity 18 is at least entirely filled andpreferably until the material rises to a certain level in all threebores 26. As the fluent material enters central bore 26, air from cavity18 escapes through the two outer bores 26. This material of course fillsthe design inscription 34 on blank surface 33. As will appear, thismaterial is preferably a synthetic resin or non-metallic plastic thatwill set, cure or otherwise harden satisfactorily in the cavity 18.

After the material has hardened within cavity 18 in the jig of FIG. 8,the nuts 38 and clamps 37 are removed and composite die member 11 simplyremoved from the jig.

As shown in FIG. 6, the insert 23 provided by the material is now inplace with the design 25 projecting into recess 15, and the die memberis ready for use in soap pressing apparatus as in FIG. 5. Also as shownin FIG. 5, the anchoring of panel 23 in place may be assured by 4providing in one or more outer bores 26 suitable fasteners such asscrews 39 that have their threaded ends 41 embedded in the plasticmaterial in the lower part of the bore and their enlarged heads 42seated in countersinks 43 at the upper ends of the bores.

As above pointed out the die member 11 is usually hard metal or plasticresistant to corrosion by acids in the soaps and by moisture. Theillustrated die member 11 is one such as heretofore used for replaceablepanels inserted into recess 18.

The master blank 32 can be an inscribed plate of any suitable material,and I have found it very satisfactory to use a hard tough machineableplastic such as the polymerized methyl methacrylate resin known asLucite, which is resistant to heat, water and the soap components andmay be easily cleanly molded or machined to provide the desired design.

A suitable parting compound such as a silicone Wax mold release iscoated over surface 33, dried and polished. Care is taken not to fillthe design inscription. This plate must be such as not to deform whenthe resin curing requires heat.

This parting compound is also spread over the entire surface of recess18 and the interior of bores 26, so that when it is desired to replaceinsert panel 23 by one having a different inscription the entirehardened plastic body may be knocked as a unit out of die 11.

The material of panel 23 must be one that is capable of being reduced tofluent condition for pouring or injecting into bore 26 and occupying thecavity including the design spaces on plate 32, and then curing in situwith substantially no shrinkage to preserve surface continuity with thedie.

Preferably the panel material is a thermosetting material that exhibitsthe following properties although thermoplastic materials may also beused. It must have low viscosity during pouring to allow the escape ofair bubbles. It must have minimum shrinkage during curing or otherwisehardening preferably a maximum of 1 to 2 percent and certainly wellunder 5 percent. It must not expand appreciably during hardening, toavoid cracking the die member or undesired distortion. The heat requiredfor hardening should be well below the heat distortion temperature ofthe die member or plate 32. In fact it is preferable to provide a resinwhich will harden within a reasonable time at room temperature.

The preferred panel material is a thermo setting resin such as one ofthe epoxy resins. One of these epoxy resins found quite satisfactory isthat known as Shell Epon 815, and its viscosity is suitably adjusted byintroduction of a diluent such as a suitable glycerol based resin. Whilethis resin will attain a suitable hardened condition at roomtemperature, I have been able to accelerate hardening somewhat byovernight storage in a F. oven. It must be appreciated that highertemperatures of hardening may introduce unwanted stresses due todifferences in thermal expansion of the die member and the insert 23.

The fasteners 39 which are used in each of bores 24 and 25 are insertedwhile the resin is still plastic, and when the resin hardens theassembly is locked together permanently.

The foregoing provides an improved method of incorporating insert panelsin soap die members which is not only speedy and inexpensive but resultsin a superior die member wherein the cast insert surface 24 is asubstantially smooth continuation of die surface 25. This insert may bespeedily and efliciently replaced by another simply by knocking out thehardened insert panel and incorporating a new one by the methoddescribed above.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics therefore. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. A composite die member for the pressing of a body of soap or the liketo a solid compact article comprising a rigid metal body having aforming surface, means in said metal forming surface defining a panelreceiving recess therein, and a fiXed hard solid non-metallic plasticpanel molded Within said recess, said panel having an exposed formingsurface that is substantially continuous With said metal forming surfaceexcept for interruption by a design formation to be imparted to thearticle formed by said die, and said panel being removable forsubstitution by molding of another design bearing panel.

2. The composite die member defined in claim 1, wherein said panel iscomposed of thermo setting material hardened within said recess.

3. The composite die member defined in claim 2, wherein said material isan epoxy resin.

4. The composite die member defined in claim 1,

UNITED STATES PATENTS 1,380,919 7/1921 Maier 18-44 2,587,297 2/ 1952Duerksen 18-44 2,656,570 11/1953 Harmon et a1 18-44 2,679,663 6/1954Schwemler et al. 18-44 XR 2,751,628 6/ 1956 Carpenter 18-47 XR 2,752,6387/1956 Anspon 18-47 XR 2,956,946 12/ 1960 Sweet et al 25-7 XR 3,094,7586/ 1963 Downie et al. 25-7 3,124,092 3/1964 Raynes 18-44 XR WILLIAM J.STEPHENSON, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,522,633 August 4, 1970 Robert Bruce Cubitt It is certified that errorappears in the above identified patent and that said Letters Patent arehereby corrected as shown below:

Column 6, line 13, "2,956,946" should read 2,965,946

Signed and sealed this 23rd day of February 1971.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

